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1、成都理工大学 硕士学位论文 基于振幅控制的Q补偿方法研究及其应用 姓名:李导 申请学位级别:硕士 专业:地球探测与信息技术 指导教师:贺振华;黄德济 20100501 摘 要 I 基于振幅控制的基于振幅控制的基于振幅控制的基于振幅控制的 Q Q Q Q 补偿方法研究及其应用补偿方法研究及其应用补偿方法研究及其应用补偿方法研究及其应用 作者简介:姓名:李导,性别:男,1985 年 2 月生,师从成都理工大学贺 振华教授,2010 年 6 月毕业于成都理工大学地球探测与信息技术专业,获得工 学硕士学位。 摘 要 地震波在地下介质中传播,由于地层吸收、散射等各种原因,地震波的能量 会衰减,地震波传播
2、时不同频率的波,传播速度不一致,高频相对于低频传播快 而引起速度频散,而速度频散导致地震子波的相位畸变。随着地震资料处理的高 分辨的要求,振幅的高保真性的技术受到关注,Q 补偿技术是一种能精确的进行 振幅恢复和相位衰减补偿的方法。 本论文从地震波传播衰减原理, 首先讨论了地震波的球面扩散, 非弹性衰减, 品质因子Q和衰减系数的相互关系;然后对地震波Q补偿的各种方法的进行了 研究,实现了基于Hargreaves波动方程精确解的吸收地震记录的正演模拟,这种 方法所合成的带吸收的地震记录包含了完整的波场信息, 其不足之处在于计算量 比较大。此外,本文开展了常规Q补偿的算法的对比研究,通过研究发现:对
3、于 延续时间较短的信号,Hargreaves方法和变型的Hale算法均可以取得较好的补偿 效果,但是Hargreaves方法运用傅里叶变换和波场延拓原理,在频率域进行叠加 成像,其计算量较大;变型的Hale算法通过目标信号与反滤波因子的褶积计算, 同时补偿了振幅和相位,计算速度较快。 在实际运用中我们发现Q值补偿方法在补偿过程中时常会出现有效信息淹 没在背景噪声中。即使输入数据没有噪声也是如此。因此,我们对Q值补偿过程 不稳定性的进行了分析,通过分析得出了Q值补偿的噪声是随着旅行时间的增加 而增加,且Q值的大小直接影响补偿结果,也影响旅行时传播距离。因此,我们 给出的建议是在实际处理结果中,Q
4、值的选取应当采取“宁大勿小”的原则,即 使选择的Q值过大,造成补偿不足,我们也可以再次进行Q补偿来弥补补偿不足。 若选择Q值过小,不仅会造成补偿过量,还会导致随着旅行时的增加,噪声过早 的出现,掩盖有效信息。 针对Q值补偿出现的问题,提出了一系列的基于振幅控制的解决方法。并进 行了一系列的数值模拟,通过数值模拟,取得了良好的效果,通过稳定性条件, 达到压制深层噪声的目的。并提出另一种先Q值补偿,再进行一个带通滤波的方 法,同样也达到了压制噪声凸显有效信息的效果,并对两种方法做出比较,指出 其中的优略性,并说明了对资料的不同,我们应当选取不同的方法,使得处理效 成都理工大学硕士学位论文 II 果
5、达到最好,而不是选取传统认为的最好的方法。 最后, 运用 Q 值补偿对实际资料中的单炮, 叠加剖面进行处理, 并进行对比, 振幅谱,相位谱,处理前后的对比效果。验证了本文提出的基于振幅控制的 Q 值补偿方法是一种使地震资料高频振幅和速度频散得到补偿的行之有效的方法。 关键词:地层吸收;振幅衰减;相位畸变;Q 补偿;振幅控制 ABSTRACT III Q compensation method based on amplitude control and its application Introduction of the author:Lidao, male, was born in Feb
6、ruary, 1985 whose tutor was Professor He Zhenhua . He graduated from Chengdu University of Technology in Earth Exploration and Information Techniques major and was granted the Master Degree in June, 2010. ABSTRACT Seismic waves in subsurface spread, due to ground absorption, scattering and other rea
7、sons, the seismic wave energy will be attenuated, seismic wave propagation in different frequency wave propagation speed is inconsistent, high frequency relative to low-frequency spread fast and cause velocity dispersion, and speed dispersion leading to the phase distortion of seismic wavelet. With
8、the high resolution seismic data processing requirements, the amplitude of the high fidelity technology concern, Q compensation is to be accurate amplitude and phase attenuation compensation recovery methods. This paper from the seismic wave attenuation principle, first discussed the seismic wave sp
9、herical spreading, non-elastic attenuation, the quality factor Q and the attenuation coefficient of the mutual relations; then seismic Q compensation of various methods were studied, based on the realization Hargreaves fluctuations Exact Solutions to the absorption of forward modeling of seismic rec
10、ords, the method with absorption of the synthesized seismic records contain information on the complete wave field, its shortcomings is larger than calculated. In addition, we carried out Q compensation algorithm of conventional comparative study, through the study found: For the short duration of t
11、he signal, Hargreaves method and variations of the Hale algorithms are able to obtain better compensation effect, but Hargreaves method using Fourier transform and the principle of wave field continuation, in the frequency domain superimposed image, the large amount of calculation; Hale algorithm va
12、riant target signal and anti-convolution filter factor calculation, while the amplitude and phase compensation, calculating speed. In practice, we found that Q values of compensation in the compensation process information often appears effective submerged in the background noise. Even if the input
13、data is not noise, too. Therefore, the Q value of the compensation process we 成都理工大学硕士学位论文 IV have not analyzed the stability, the Q value obtained by analyzing the noise compensation, with the increase of travel time, and the Q value of the size of the direct impact on compensation for the results,
14、 but also affect the travel propagation distance. Therefore, we recommend given the results in the actual processing, Q value is selected to be taken rather big not to small principle, even if the choice of Q value is too large, resulting in inadequate compensation and we can compensate to make up a
15、gain Q inadequate compensation. If you choose to Q value is too small, not only will cause excessive compensation, but also lead to travel with the increase of noise occurs too early, cover up useful information. Q value of compensation for the problems, proposed a series of amplitude-based control
16、solution. And a series of numerical simulation, the numerical simulation, and achieved good results, the stability conditions, to suppress the deep noise. And made another first-Q compensation, to conduct a band pass filter method also achieved effective suppression of information highlighting the effect of noise, and make a comparison of two methods, pointing out the advantages and strategic nature, and explains